<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    let x=3;
    let y=4;
     x=x+y;
     y=x-y;
     x=x-y;
    alert(x);
    alert(y);
</script>
</body>
</html>